Image forming apparatus and data transfer method

ABSTRACT

An image forming apparatus includes an image forming unit including a scanner and a printer, a server, and a local network circuit connecting the image forming unit and the server. In each of the image forming unit and the server, a hardware processor selects one of a first communication protocol and a second communication protocol in accordance with data to be transmitted by a transceiver. The first communication protocol includes a provision for ensuring reliability of communication, and the second communication protocol does not include a provision for ensuring reliability of communication.

The entire disclosure of Japanese Patent Application No. 2019-120745,filed on Jun. 28, 2019, is incorporated herein by reference in itsentirety.

BACKGROUND Technological Field

The present disclosure relates to an image forming apparatus and moreparticularly to a server-contained image forming apparatus and a datatransfer method inside the image forming apparatus.

Description of the Related Art

Multi Functional Peripherals (MFPs) that combine a copier, a printer, afacsimile, and the like are known. Conventionally, to construct anetwork environment in an office, for example, a server need to beseparately prepared in addition to MFPs.

In recent years, there have been proposed MFPs that contain a server inthe housing of the MFP (hereinafter referred to as server-contained MFP)so as to construct a network only by introducing an MFP alone. Anexample of the related arts disclosing server-contained MFPs is JapaneseLaid-Open Patent Publication No. 2018-109698.

SUMMARY

In a server-contained MFP, the conventional MFP part (hereinafterreferred to as an image forming unit) shares a touch panel with thecontained server. However, the communication scheme used between theimage forming unit and the server is basically the same as thecommunication scheme used between the image forming unit and an externalserver.

For example, for a communication protocol between the image forming unitand the server, TCP ensuring the content of communication is used as itis although they are in the same housing. Therefore, when the imageforming unit and the server cooperate to transfer a large volume ofimage data, the communication takes long time and burdens acommunication circuit.

The present disclosure is made in view of the problem described above.An object of the present disclosure is to reduce the time taken for datatransfer between an image forming unit and a server in an image formingapparatus in which the image forming unit and the server are connectedthrough a local network circuit.

To achieve at least one of the abovementioned objects, according to anaspect of the present invention, an image forming apparatus reflectingone aspect of the present invention comprises an image forming unit, aserver, and a local network circuit. The image forming unit includes ascanner configured to scan a document to generate image data and aprinter configured to print image data generated by the scanner oranother image data on a recording medium. The local network circuit isconfigured to connect the image forming unit and the server. The imageforming unit and the server each include a transceiver and a hardwareprocessor. The transceiver transmits and receives data through the localnetwork circuit. The hardware processor of one of the image forming unitand the server selects one of a first communication protocol and asecond communication protocol in accordance with data transmitted by thetransceiver of the one of the image forming unit and the server whendata is transmitted by the transceiver of the one to the transceiver ofthe other. The first communication protocol includes a provision forensuring reliability of communication, and the second communicationprotocol does not include a provision for ensuring reliability ofcommunication.

In another aspect, a data transfer method in an image forming apparatusis provided. The image forming apparatus includes an image forming unitincluding a scanner configured to scan a document to generate image dataand a printer configured to print image data generated by the scanner oranother image data on a recording medium, a server, and a local networkcircuit configured to connect the image forming unit and the server. Thedata transfer method comprises: selecting one of a first communicationprotocol and a second communication protocol in accordance with data tobe transmitted, by a transmitter side of the image forming unit and theserver, when data is transferred between the image forming unit and theserver through the local network circuit; and transmitting data by thetransmitter side to a receiver side using the selected communicationprotocol. Here, the first communication protocol includes a provisionfor ensuring reliability of communication, and the second communicationprotocol does not include a provision for ensuring reliability ofcommunication.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages and features provided by one or more embodiments of theinvention will become more fully understood from the detaileddescription given hereinbelow and the appended drawings which are givenby way of illustration only, and thus are not intended as a definitionof the limits of the present invention.

FIG. 1 is an overall perspective view showing an external configurationof an image forming apparatus 500.

FIG. 2 is a block diagram illustrating an example of the hardwareconfiguration of image forming apparatus 500.

FIG. 3 is a block diagram mainly illustrating a communication functionas a part of the functions of an image forming unit 30 and a server 50.

FIG. 4 is a flowchart showing a communication protocol switchingoperation and data transmission performed on the transmitter side ofimage forming apparatus 500.

FIG. 5 is a flowchart showing an example of the process in step S100 inFIG. 4 in more detail.

FIG. 6 is a flowchart showing another process example in step S100 inFIG. 4.

FIG. 7 is a flowchart showing yet another example of the process in stepS100 in FIG. 4.

FIG. 8A is a flowchart showing the procedure of preview in the imageforming apparatus in a second embodiment.

FIG. 8B is a flowchart showing the procedure of preview in the imageforming apparatus in the second embodiment.

FIG. 9A is a flowchart showing the procedure of an OCR process in imageforming apparatus 500 in a third embodiment.

FIG. 9B is a flowchart showing the procedure of an OCR process in imageforming apparatus 500 in the third embodiment.

FIG. 10A is a flowchart showing the procedure of pull print in imageforming apparatus 500 in a fourth embodiment.

FIG. 10B is a flowchart showing the procedure of pull print in imageforming apparatus 500 in the fourth embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, one or more embodiments of the present invention will bedescribed with reference to the drawings. However, the scope of theinvention is not limited to the disclosed embodiments.

When number, volume, etc. are referred to in the embodiments describedbelow, the scope of the present disclosure is not necessarily limited tothe noted number, volume, etc. unless otherwise specified.

In the figures, the drawings are not necessarily drawn to scale and thescale may be changed in the drawings so as to clarify a structure foreasy understanding of the structure. The same or corresponding parts aredenoted by the same reference signs and a description thereof will notbe repeated. The embodiments described below may be selectively combinedas appropriate.

First Embodiment A. Hardware Configuration

First of all, a hardware configuration in the present embodiment isdescribed.

FIG. 1 is an overall perspective view showing an external configurationof an image forming apparatus 500. Image forming apparatus 500 includesan image forming unit 30 and a server 50.

Image forming unit 30 is a part corresponding to a conventional MFP thatdoes not contain a server. An example of the hardware configuration ofimage forming unit 30 is described later with reference to FIG. 2.

Server 50 is connected to image forming unit 30 through a local networkcircuit (reference sign 110 in FIG. 2). In the present example, thelocal network is a network internal to image forming apparatus 500.Image forming unit 30 functions as a client device of server 50. Anexample of the hardware configuration of server 50 is described laterwith reference to FIG. 2.

In the present embodiment, image forming unit 30 and server 50 arecontained in one housing 500F to configure a server-contained MFP.However, image forming unit 30 and server 50 are not necessarilycontained in the same housing as long as they are connected throughlocal network circuit 110 and thereby configured integrally.

FIG. 2 is a block diagram illustrating an example of the hardwareconfiguration of image forming apparatus 500. Referring to FIG. 2, imageforming apparatus 500 includes image forming unit 30, server 50, andlocal network circuit 110.

Image forming unit 30 includes a control unit 31, a touch panel 36, anetwork controller 39, a scanner 40, and a printer 41.

Touch panel 36 includes a touchpad as an input device 37 for a varietyof inputs and a liquid crystal panel or organic electro-luminescence(EL) display as a display device 38 for a variety of display. With sucha configuration, the user directly touches the screen of touch panel 36whereby the user can operate image forming unit 30 or server 50. Insteadof touch panel 36, for example, a button input-type operation panel asinput device 37 and a display panel as display device 38 may beseparately provided. Touch panel 36 is used also for operation of server50, and image forming unit 30 and server 50 share touch panel 36.

Network controller 39 connects image forming unit 30 to a communicationnetwork including a wired local area network (LAN) such as Ethernet(registered trademark) or a wireless LAN. Network controller 39 is notcontained in control unit 31 in FIG. 2 but may be contained in controlunit 31.

Scanner 40 optically reads a document set on a platen (not shown) toconvert characters, symbols, images, and the like recorded on thedocument into image data (also referred to as “document image”).Optically reading a document may be referred to as “scanning” or “scan”.Scanning by scanner 40 is performed, for example, based on the user'soperation on touch panel 36. CPU 32 of control unit 31 transmits adocument image obtained by scanning a document to server 50 throughnetwork controller 39. CPU 32 transmits the scanned document image toanother image forming apparatus, a server, a personal computer (PC), andthe like connected to external network 510, through a security gateway60.

Printer 41 forms a document image generated using scanner 40 and imagedata (also referred to as “copy image”) generated from print datatransmitted from an external PC or the like, on a recording medium suchas paper. As used herein print data is obtained by converting arendering instruction issued by an operating system or an applicationprogram of a PC into a rendering instruction in a page descriptionlanguage, or is document data described in a file format such asPortable Document Format (PDF), Tagged Image File Format (TIFF), JointPhotographic Experts Group (JPEG), and XML Paper Specification (XPS).The rendering instruction converted into a page description language canbe processed by printer 41 using a printer driver. Examples of methodsof printing by printer 41 include electrophotography and inkjet.

Control unit 31 controls the entire image forming unit 30. Control unit31 includes a central processing unit (CPU) 32, an auxiliary storagedevice 33, a read only memory (ROM) 34, and a random access memory (RAM)35.

CPU 32 as a hardware processor operates in accordance with instructionsof a program to perform numerical operations or determine conditions.

Auxiliary storage device 33 is a nonvolatile memory for storing imagedata, for example. Auxiliary storage device 33 is implemented by, forexample, a hard disk drive (HDD), a solid state drive (SSD), a digitalversatile disc-read only memory (DVD-ROM), a magnetic disc, an opticaldisc, a universal serial bus (USB) memory, or a floppy disc (registeredtrademark). Auxiliary storage device 33 stores document image scanned byscanner 40, print data, and the like.

Read only memory (ROM) 34 is a read-only nonvolatile memory. ROM 34stores, for example, a program executed by CPU 32.

Random access memory (RAM) 35 is a volatile memory in which read andwrite is performed freely, and is used as a working area when a programis executed by CPU 32. RAM 35 includes, for example, a dynamic RAM(DRAM) and a static RAM (SRAM).

Server 50 includes a CPU 51, a ROM 52, a RAM 54, an auxiliary storagedevice 53, and a network controller 55 and shares touch panel 36 withimage forming unit 30.

The configuration of CPU 51, ROM 52, auxiliary storage device 53, RAM54, and network controller 55 are similar to the configuration of CPU32, ROM 34, auxiliary storage device 33, and RAM 35 included in controlunit 31 of image forming unit 30. The foregoing description of theelements that constitute server 50 will not be repeated.

Server 50 is connected to local network circuit 110 through networkcontroller 55. Control unit 31 of image forming unit 30 is connected tocommon local network circuit 110 through network controller 39. The usertherefore can use an application installed in server 50 using touchpanel 36 to implement the function that image forming unit 30 and server50 cooperate to perform. Examples of the function that image formingunit 30 and server 50 cooperate to perform include a preview function,an OCR function, and a pull print function in an application on server50. These functions will be described in the second, third, and fourthembodiments.

In the present embodiment, local network circuit 110 is connected to anexternal network 510 through security gateway 60. However, local networkcircuit 110 and external network 510 are not necessarily connected toeach other.

Security gateway 60 is a device interposed between local network circuit110 and external network 510 for protecting the system from threats suchas external computer viruses and hacking. Data transmission/receptionbetween local network circuit 110 and external network 510 is performedthrough security gateway 60. Security gateway 60 may be a device inwhich a plurality of functions for enhancing security of a network, suchas firewall, antivirus, and content filtering, are consolidated in onepiece, that is, a unified threat management (UTM) device. Alternatively,security gateway 60 may be a device in which a device for firewall, adevice for content filtering, and the like are combined as appropriate.

B. Functional Configuration

[Functional Configuration of Image Forming Apparatus 500]

Specific functions in image forming apparatus 500 of the presentembodiment, specifically, a communication function between image formingunit 30 and server 50 will now be described. FIG. 3 is a block diagrammainly illustrating the communication function as a part of thefunctions of image forming unit 30 and server 50. Communication betweenimage forming unit 30 and server 50 is performed through local networkcircuit 110.

Image forming unit 30 includes, as its functional configuration, acommunication protocol selector 70, an encoder 72, a decoder 75, and atransceiver 80.

The functions of communication protocol selector 70, encoder 72, anddecoder 75 are implemented by CPU 32 in FIG. 2 operating in accordancewith a program stored in ROM 34. The function of transceiver 80 isimplemented by CPU 32 in FIG. 2 operating in accordance with a programto control network controller 39.

Communication protocol selector 70 selects a protocol to be used forcommunication. Communication protocol selector 70 selects one of TCP asa first communication protocol and UDP as a second communicationprotocol in accordance with data transmitted by transceiver 80 and adestination.

Encoder 72 and decoder 75 encode or decode data transmitted or receivedby transceiver 80, if encoding or decoding is necessary. Examples ofencoding include compression, encryption, or data format conversion. Inanother aspect, conversion to PDF may be performed as data formatconversion.

Transceiver 80 transmits/receives data using a communication protocolselected by communication protocol selector 70.

On the other hand, server 50 includes, as its functional configuration,a communication protocol selector 90, an encoder 91, a decoder 92, animage processor 94, and a transceiver 100.

The functions of communication protocol selector 90, encoder 91, decoder92, and image processor 94 are implemented by CPU 51 in FIG. 2 operatingin accordance with a program stored in ROM 52. The function oftransceiver 100 is implemented by CPU 51 in FIG. 2 operating inaccordance with a program to control network controller 55.

The functional configuration of communication protocol selector 90,encoder and decoder 92, and transceiver 100 of server 50 are similar tothe functional configuration of communication protocol selector 70,encoder and decoder 75, and transceiver 80 of image forming unit 30. Thedescription of the above elements that constitute server 50 will not berepeated.

Image processor 94 performs image processing such as an OCR process onthe received data. The details of the OCR process will be described inthe third embodiment.

[Targeted Network Model and Layers]

A network model used in the present embodiment will be described below.

For example, the Open Systems Interconnection (OSI) reference model orthe Transmission Control Protocol/Internet Protocol (TCP/IP) model arecommonly known as a model representing the functions of a network inlayers.

In the present embodiment, among network models, the TCP/IP model widelyprevalent is used. The functions of TCP/IP model are configured based onthe following four-layer model. The layers are built up in the followingorder from bottom: the network interface layer, the internet layer, thetransport layer, and the application layer. The function used in a layeris used in the higher-level layer. The features of the layers will bedescribed briefly below.

The network interface layer implements communication with a devicedirectly connected to a device on the transmitter side. Examples of thecommunication protocol of this layer include Ethernet configuring awired network and Wi-Fi (Wireless Fidelity) (registered trademark) thatis a typical standard of wireless LANs.

The internet layer adds a function such as relaying using the functionof the network interface layer and implements communication with adevice not directly connected to a device on the transmitter side, thatis, a device in another network. An example of the communicationprotocol of this layer is IP that is one of main protocols thatconfigure the TCP/IP model.

The transport layer controls data transfer using the function of theinternet layer. Examples of the communication protocol of this layerinclude TCP and User Datagram Protocol (UDP). The detail of TCP and UDPwill be described later.

The application layer implements the functions of individualapplications using the function of the transport layer. Examples of thecommunication protocol of this layer include Hyper Text TransferProtocol (HTTP) that is a protocol for accessing a web site, Simple MailTransfer Protocol (SMTP) that is a protocol for transmitting emails, andDomain Name System (DNS) that is a communication protocol translatingdomain names to IP addresses.

TCP and UDP that are main communication protocols in the transport layerwill be described below.

TCP includes a provision for performing communication after establishinga connection before starting communication and disconnecting aconnection when terminating communication. TCP further includesprovisions for ensuring reliability of communication, such as ensuringthe order of packets with sequential numbers, checking whether receiveddata has an error, checking that the other party receives data withouterrors, and requesting retransmission of unreceived data. In this way,in communication via TCP, since the connecting and disconnecting processand the process for ensuring the reliability of communication areperformed, the time required for communication is longer compared withcommunication via UDP.

TCP is widely used in network applications that require reliability ofcommunication, such as HTTP in the Web or SMTP for mailtransmission/reception.

Unlike TCP, UDP includes a provision for sending data withoutestablishing a connection in advance. Unlike TCP, UDP does not include aprovision for ensuring the reliability of communication. The timerequired for communication using UDP is therefore shorter than the timerequired for communication using TCP.

UDP is often used when reduction of communication time has precedenceover ensuring the reliability of the content of communication, as is thecase with DNS frequently inquiring a server, sound and video streaming,or Internet telephony.

In the present embodiment, each of communication protocol selector 70 ofimage forming unit 30 and communication protocol selector 90 of serverunit 50 selects one of TCP and UDP described above as a protocol of thetransport layer, in accordance with data to be transmitted and adestination Referring to FIG. 4 to FIG. 7, selection of a communicationprotocol will be described below in more detail.

The selected communication protocol of the transport layer is notlimited to TCP and UDP described above. More generally, a communicationprotocol that has a provision ensuring the reliability of communicationas in TCP is denoted as a first communication protocol, and acommunication protocol that does not have a provision ensuring thereliability of communication as in UDP is denoted as a secondcommunication protocol. In this case, each communication protocolselector 70, 90 selects one of the first communication protocol and thesecond communication protocol in accordance with data to be communicatedand a destination.

C. Operation Overview

In the following description, “transmitter side” and “receiver side” maybe referred in connection with data transfer between image forming unit30 and server 50. Specifically, when data is transmitted from imageforming unit 30 to server 50, image forming unit 30 corresponds to thetransmitter side and server 50 corresponds to the receiver side. In theopposite case, server 50 corresponds to the transmitter side and imageforming unit 30 corresponds to the receiver side.

Referring to FIG. 4, a control structure of image forming apparatus 500will be described. FIG. 4 is a flowchart showing a main process for acommunication protocol switching operation and data transmissionperformed on the transmitting side of image forming apparatus 500.

In step S100, communication protocol selector 70 or 90 on thetransmitter side in FIG. 3 determines which of TCP and UDP to select inaccordance with data to be transmitted and a destination. The detail ofprocessing in step S100 will be described with reference to FIG. 5 toFIG. 7.

In step S101, if the selected communication protocol is UDP (YES in stepS101), communication protocol selector 70 or 90 on the transmitter sideproceeds to step S102. In step S102, transceiver 80 or 100 on thetransmitter side in FIG. 3 transmits data to transceiver 80 or 100 onthe receiver side, using UDP as the communication protocol of thetransport layer.

On the other hand, in step S101, if the selected communication protocolis not UDP (NO in step S101), communication protocol selector 70 or 90on the transmitter side proceeds to step S103. In step S103, transceiver80 or 100 on the transmitter side transmits data to transceiver 80 or100 on the receiver side, using TCP as the communication protocol of thetransport layer.

[Transmission of Data from Image Forming Unit 30 to Server 50]

FIG. 5 is a flowchart showing an example of the process in step S100 inFIG. 4 in more detail. The flowchart in FIG. 5 shows an example of thecriterion by which a communication protocol is selected when data istransmitted from image forming unit 30 to server 50.

Referring to FIG. 5, in step S201, communication protocol selector 70 ofimage forming unit 30 in FIG. 3 determines whether the transmissiondestination of data is server 50. If the transmission destination is notserver 50 (NO in step S201), communication protocol selector 70 proceedsto step S206. The transmission destination of data in this case is adevice connected to external network 510 in FIG. 2. In step S206,communication protocol selector 70 then selects TCP as the communicationprotocol of the transport layer. Since the reliability of communicationis thus ensured, the risk of data tampering is reduced when imageforming unit 30 communicates with a device connected to the externalnetwork.

On the other hand, if the transmission destination is server 50 (YES instep S201), communication protocol selector 70 proceeds to step S202.

In step S202, communication protocol selector 70 of image forming unit30 determines whether data transmitted by transceiver 80 is an imagelog. If data transmitted by transceiver 80 is an image log (YES in stepS202), communication protocol selector 70 selects UDP as thecommunication protocol of the transport layer in step S207. The processthereafter returns to the main process.

Here, the image log in the present embodiment refers to data in which alog of a job executed by image forming unit 30 is stored as image data.Image forming unit 30 transmits image data treated in a job as an imagelog, together with the log of the job, to the server, thereby allowingthe user to learn later what image is printed or transmitted by imageforming unit 30. This function is referred to as image log transferfunction.

When image forming unit 30 performs the image log transfer function,image transfer from image forming unit 30 to server 50 occurs inaddition to execution of a variety of jobs in image forming unit 30.Delay in the image transfer affects execution of a variety of jobs inimage forming unit 30. For example, it affects execution of atransmission-related job such as Scan to E-mail that transmits scan databy email to a device connected to the external network. In the case inthe present embodiment, since an image log is transferred via UDP, delayin image log transfer can be prevented, unlike conventional transfer viaTCP. This can suppress the effect on other transmission-related jobs inwhich communication is performed via TCP.

In an image log, at least one of encryption, data compression, orconversion to PDF is performed. Therefore, when a communication erroroccurs due to noise or the like, the receiver side fails to decode,decompress, or read PDF in an image log, so that the user can detectoccurrence of the communication error. The transfer of an image log fromimage forming unit 30 to server 50 is performed using local networkcircuit 110. The risk of data tampering from the outside is low.

Next, if data transmitted by transceiver 80 is not an image log (NO instep S202), communication protocol selector 70 proceeds to step S203.

In step S203, communication protocol selector 70 of image forming unit30 determines whether data transmitted by transceiver 80 is export data.Export data refers to backup data of current setting information ofimage forming unit 30 that is transmitted by transceiver 80 of imageforming unit 30 to transceiver 100 of server 50. Export data is usuallyencrypted. If data transmitted by transceiver 80 is export data (YES instep S203), communication protocol selector 70 selects UDP in step S207.Even when a communication error occurs due to noise or the like, theencrypted export data is unable to be decrypted on the receiver side, sothat the receiver side can detect occurrence of a communication error.The process thereafter returns to the main process.

On the other hand, if data transmitted by transceiver 80 is not exportdata (NO in step S203), communication protocol selector 70 proceeds tostep S204.

In step S204, communication protocol selector 70 of image forming unit30 determines whether data transmitted by transceiver 80 is scan data.Scan data refers to image data generated by scanner 40 of image formingunit 30. If data transmitted by transceiver 80 is scan data (YES in stepS204), communication protocol selector 70 selects UDP in step S207.Here, even when a communication error occurs due to noise or the like,some pixels are merely missing in the scan data, which practically doesnot matter. Using UDP for scan data gives precedence to reduction of thetime required for communication over ensuring the reliability of thecontent of communication. The process thereafter returns to the mainprocess.

On the other hand, if data transmitted by transceiver 80 is not scandata (NO in step S204), communication protocol selector 70 proceeds tostep S205.

In step S205, communication protocol selector 70 of image forming unit30 determines whether data transmitted by transceiver 80 is data equalto or larger than a predetermined size. If data transmitted bytransceiver 80 is data equal to or larger than a predetermined size (YESin step S205), communication protocol selector 70 selects UDP in stepS207. Using UDP for data equal to larger than a predetermined size givesprecedence to reduction of the time required for communication overensuring the reliability of the content of communication. The processthereafter returns to the main process.

On the other hand, if data transmitted by transceiver 80 is not dataequal to or larger than a predetermined size (NO in step S205),communication protocol selector 70 selects TCP in step S206.

Image forming unit 30 may simultaneously transmit scan data or the liketo server 50 and a device such as a server or a PC connected to externalnetwork 510, for example, for sharing documents. In this case, the datais processed for each destination in accordance with the flowchartillustrated in FIG. 5. For example, in this example, data transferred byimage forming unit 30 to server 50 follows the branch to YES in stepS201. On the other hand, data transmitted by image forming unit 30 to adevice connected to external network 510 follows the branch to NO instep S201. This is applicable to the following third and fourthembodiments.

[Transmission of Data from Server 50 to Image Forming Unit 30]

FIG. 6 is a flowchart showing another process example in step S100 inFIG. 4. FIG. 6 shows an example of the criterion by which acommunication protocol is selected when data is transmitted from server50 to image forming unit 30.

Referring to FIG. 6, in step S251, communication protocol selector 90 ofserver 50 in FIG. 3 determines whether the transmission destination ofdata is image forming unit 30. If the transmission destination is notimage forming unit 30 (NO in step S251), communication protocol selector90 proceeds to step S255. Then, in step S255, communication protocolselector 90 selects TCP as the communication protocol of the transportlayer.

On the other hand, if the transmission destination is image forming unit30 (YES in step S251), communication protocol selector 90 proceeds tostep S252.

In step S252, communication protocol selector 90 of server 50 determineswhether data transmitted by transceiver 80 is import data. Import datarefers to change data of setting information of the image forming unitthat is transmitted by transceiver 100 of server 50 to transceiver 80 ofimage forming unit 30. Import data is usually subjected to encryptionand data compression. Therefore, if data transmitted by transceiver 80is import data (YES in step S252), communication protocol selector 90selects UDP as the communication protocol of the transport layer in stepS256, in the same manner as for export data. The process thereafterreturns to the main process.

On the other hand, if data transmitted by transceiver 100 is not importdata (NO in step S252), communication protocol selector 90 proceeds tostep S253.

In step S253, communication protocol selector 90 of server 50 determineswhether data transmitted by transceiver 80 is update data of firmware(FW) for the image forming unit. The FW data transmitted to imageforming unit 30 may be update data of the entire firmware or may beupdate data of part of firmware. FW data usually includes an errordetection code such as checksum.

If data transmitted by transceiver 80 is FW data (YES in step S253),communication protocol selector 90 selects UDP as the communicationprotocol of the transport layer in step S256. Here, even when acommunication error occurs due to noise or the like, the receiver sidecan detect occurrence of a communication error using an error detectioncode, and therefore it does not matter if UDP that does not ensure thereliability of communication is used.

On the other hand, if data transmitted by transceiver 100 is not FW data(NO in step S253), communication protocol selector 90 proceeds to stepS254.

In step S254, communication protocol selector 90 of server 50 determineswhether data transmitted by transceiver 80 is data equal to or largerthan a predetermined size. If data transmitted by transceiver 100 isdata equal to or larger than a predetermined size (YES in step S254),communication protocol selector 90 selects UDP in step S256. The processthereafter returns to the main process.

On the other hand, if data transmitted by transceiver 100 is not dataequal to or larger than a predetermined size (NO in step S254), in stepS255, communication protocol selector 90 selects TCP.

[Other Modifications]

FIG. 7 is a flowchart showing yet another example of the process in stepS100 in FIG. 4. The process shown in FIG. 7 can be considered as aprocess in which the process shown in FIG. 5 and the process shown inFIG. 6 are combined in view of kinds of transmission data.

In step S301, communication protocol selector 70 or 90 on thetransmitter side in FIG. 3 determines whether the transmissiondestination of data is a server or an image forming unit connected tothe same local network. If the transmission destination is not a serveror an image forming unit connected to the same local network circuit 110(NO in step S301), communication protocol selector 70 or 90 on thetransmitter side proceeds to step S305. The transmission destination ofdata in this case is a device connected to external network 510 in FIG.2. Therefore, in step S301, the communication protocol selector on thetransmitter side selects TCP as the communication protocol of thetransport layer.

On the other hand, if the transmission destination is server 50 or imageforming unit 30 connected to the same local network (YES in step S301),communication protocol selector 70 or 90 on the transmitter sideproceeds to step S302.

In step S302, communication protocol selector 70 or 90 on thetransmitter side determines whether data transmitted by the transceiveron the transmitter side is encoded data or data including an errordetection code. Encoding refers to encryption or compression. The imagelog in step S202 and export data in step S203 in FIG. 5, and import datain step S252 in FIG. 6 correspond to encoded data. FW data in step S253in FIG. 6 corresponds to data including an error detection code. If datatransmitted by transceiver 80 is encoded data or data including an errordetection code (YES in step S302), communication protocol selector 70 or90 on the transmitter side selects UDP in step S306. The processthereafter returns to the main process.

On the other hand, data transmitted by the transceiver on thetransmitter side is not encoded data or data including an errordetection code (NO in step S302), communication protocol selector 70 or90 on the transmitter side proceeds to step S303.

In step S303, communication protocol selector 70 or 90 on thetransmitter side determines whether data transmitted by the transceiveron the transmitter side is scan data. Step S303 corresponds to step S204in FIG. 5. If data transmitted by the transceiver on the transmitterside is scan data (YES in step S303), the communication protocolselector on the transmitter side selects UDP in step S306. The processthereafter returns to the main process.

On the other hand, if data transmitted by the transceiver on thetransmitter side is not scan data (NO in step S303), the communicationprotocol selector on the transmitter side proceeds to step S304.

In step S304, communication protocol selector 70 or 90 on thetransmitter side determines whether data transmitted by the transceiveron the transmitter side is data equal to or larger than a predeterminedsize. Step S304 corresponds to step S205 in FIG. 5 and step S304 in FIG.6. If data transmitted by the transceiver on the transmitter side isdata equal to or larger than a predetermined size (YES in step S304),the communication protocol selector on the transmitter side selects UDPin step S306. The process thereafter returns to the main process.

On the other hand, if data transmitted by the transceiver on thetransmitter side is not scan data (NO in step S304), communicationprotocol selector 70 or 90 on the transmitter side selects TCP in stepS305.

D. Effects of First Embodiment

As described above, the image forming apparatus in the first embodimentis directed to a server-contained image forming apparatus. Specifically,when server 50 and image forming unit 30 (that is, the partcorresponding to a conventional MFP) inside the image forming apparatustransfer data, UDP is used instead of TCP as the communication protocol,depending on data to be transmitted. This can reduce the data transfertime between server 50 and image forming unit 30 and therefore canimprove the processing performance when server 50 and image forming unit30 operate in cooperation with each other.

Specifically, transfer data for which UDP is used as the communicationprotocol of the transport layer includes, for example, an image log,setting information of the image forming unit (import data, exportdata), update data of firmware, or scan data.

The image log is data, for example, subjected to encryption,compression, or conversion to PDF. The setting information of the imageforming unit is encoded, for example, encrypted or compressed data,similar to the image log, and the update data of firmware includes anerror detection code. In any case, occurrence of a communication errorcan be detected on the receiver side. In the case of scan data,practically it does not matter if some of pixels are missing due to acommunication error by noise or the like. Hence, as for transfer ofthese data, UDP that puts emphasis on communication speed is preferableto using TCP that ensures the reliability of communication, in terms ofimproving the performance of the server-contained MFP.

Second Embodiment

A second embodiment will be described below. In the second embodiment,the cooperative operation between image forming unit 30 and server 50 insuch a case that a document image scanned by image forming unit 30 ispreviewed on server 50 will be described. The hardware configuration andthe functional configuration related to data transfer of the imageforming apparatus in the second embodiment are similar to thosedescribed with reference to FIG. 2 and FIG. 3 in the first embodimentand will not be further elaborated.

Referring to FIG. 2, FIG. 8A, and FIG. 8B, a control structure of theimage forming apparatus according to the second embodiment will bedescribed. FIG. 8A and FIG. 8B are flowcharts showing the procedure ofpreview in the image forming apparatus in the second embodiment. In thesecond embodiment, transceiver 80 of image forming unit 30 transmits adocument image obtained by a scan by scanner 40 to transceiver 100 ofserver 50, and server 50 previews the document image.

As shown in FIG. 8A, in step S400, CPU 51 of server 50 in FIG. 2 waitsfor a user to log in through input device 37. Since it is premised thatthe function in the present second embodiment is the functionimplemented mainly by an application in server 50, user login isdetermined in server 50. User login can be determined either by anapplication on image forming unit 30 or by an application on server 50,and the device that a user logs in to is not limited.

In step S402, CPU 51 determines whether a user has logged in. If a userhas logged in (YES in step S402), CPU 51 stores login information andjob information into auxiliary storage device 53 or RAM 54 and proceedsto step S404. The login information is information indicating that theuser has logged in and includes, for example, user identificationinformation such as user name, user ID, and password. The jobinformation is, for example, information for specifying the job such asjob name and job creation date and time. If the user has not logged in(NO in step S402), CPU 51 returns to step S400.

In step S404, CPU 51 notifies CPU 32 of image forming unit 30 of theuser login information stored in auxiliary storage device 53 or RAM 54through network controller 55. When notification of login information isgiven, TCP is used as the communication protocol of the transport layer.This is applicable to the following third and fourth embodiments. CPU 51thereafter proceeds to step S406.

In step S450, CPU 32 of image forming unit 30 receives the logininformation transmitted from server 50 through network controller 39,and CPU 32 proceeds to step S452.

In step S452, CPU 32 updates the storage area for login information inauxiliary storage device 33 or

RAM 35 with the received login information and then proceeds to stepS454.

In step S406, CPU 51 of server 50 starts an application for preview,based on an instruction by the user through input device 37, andproceeds to step S408.

In step S408, CPU 51 notifies image forming unit 30 of the jobinformation stored in auxiliary storage device 53 or RAM 54 throughnetwork controller 55 and proceeds to step S410. TCP is used as thecommunication protocol of the transport layer when notification of jobinformation is given. TCP is used similarly in the following third andfourth embodiments.

In step S454, CPU 32 of image forming unit 30 receives notification ofthe job information from server 50 through network controller 39.

In step S410, CPU 51 of server 50 starts a job and notifies imageforming unit 30 of the job start through network controller 55.

In step S456, CPU 32 of image forming unit 30 receives notification ofthe job start from server 50 through network controller 39 and proceedsto step S458.

In step S458, CPU 32 of image forming unit 30 instructs scanner 40 toscan a document, and scanner 40 starts scanning. CPU 32 thereafternotifies server 50 of the start of document reading through networkcontroller 39. TCP is used as the communication protocol of thetransport layer when notification of the start or termination ofdocument reading is given, and TCP is used similarly in the followingthird and fourth embodiments.

In step S412, CPU 51 of server 50 receives the notification of the startof document reading transmitted from image forming unit 30 throughnetwork controller 55.

In step S460, CPU 32 (that is, communication protocol selector 70 inFIG. 3) of image forming unit 30 determines whether the job iscooperating with an application on server 50, based on the jobinformation. In this process example, the job is cooperating with anapplication on server 50 (YES in step S460), and CPU 32 proceeds to stepS464. In step S464, CPU 32 selects UDP as the communication protocol ofthe transport layer in transmission of data from image forming unit 30to server 50. CPU 32 then proceeds to step S466 in FIG. 8B.

Unlike the present example, in step S460, if CPU 32 (that is,communication protocol selector 70 in FIG. 3) determines that the job isnot cooperating with an application on server 50 (NO in step S460), theprocess proceeds to step S462. Examples include a case where the serverpreviews a document image read by another image forming apparatusconnected to the external network. In step S462, CPU 32 selects TCP asthe communication protocol of the transport layer in transmission ofdata from image forming unit 30 to server 50.

In step S466, CPU 32 (that is, transceiver 80 in FIG. 3) transmits theimage data read by scanner 40 to server 50 through network controller39. In doing so, transceiver 80 transmits data in accordance with thecommunication protocol of the transport layer selected in step S462 orstep S464. In this process example, UDP is selected in step S464 anddata is transmitted using UDP.

In step S414, CPU 51 of server 50 receives the image data transmittedfrom image forming unit 30 through network controller 55. CPU 51thereafter stores the received image data into auxiliary storage device53 and proceeds to step S416.

In step S416, CPU 51 starts preview by displaying the image data storedin auxiliary storage device 53 in step S414 on display device 38.

In step S468, CPU 32 of image forming unit 30 terminates documentreading by scanner 40 and terminates transmission of an image to server50 through network controller 39. CPU 32 then notifies server 50 ofthese termination and proceeds to step S470. TCP is used as thecommunication protocol of the transport layer in notification oftermination of data transmission. TCP is used similarly in the followingthird and fourth embodiments.

In step S418, CPU 51 of server 50 receives the notification thatdocument reading by image forming unit 30 and transmission of an imageto server 50 are terminated through network controller 55 and proceedsto step S420.

In step S420, CPU 51 gives an instruction to display device 38 toterminate the preview and proceeds to step S422.

In step S422, CPU 51 terminates the application for preview and proceedsto step S424.

In step S424, CPU 51 proceeds to step S426 in response to the userlogging out using input device 37.

In step S426, CPU 51 gives notification of logout information to imageforming unit 30 through network controller 55 and terminates a series ofprocess steps. The logout information is information indicating that theuser has logged out and includes, for example, user identificationinformation such as user name and user ID. TCP is used as thecommunication protocol of the transport layer in notification of logoutinformation. TCP is used similarly in the following third and fourthembodiments.

In step S470, CPU 32 of image forming unit 30 receives the logoutinformation from server 50 through network controller 39 and proceeds tostep S472.

In step S472, CPU 32 updates the storage area for logout information inauxiliary storage device 33 or

RAM 35 with the received logout information and terminates a series ofprocess steps.

Effects of Second Embodiment

Conventionally, the document reading in image forming unit 30 has beenspeeded up year by year, for example, by reading both sidessimultaneously. Meanwhile, it takes time to transfer a read documentimage from image forming unit 30 to server 50. Consequently, it has beendifficult to preview the document image read by image forming unit 30 inreal time in the application on server 50.

By contrast, the image forming apparatus in the second embodiment usesUDP as the communication protocol when transferring the read image fromimage forming unit 30 to server 50 and thus can reduce the time taken totransfer the document image. The real-time performance in preview of adocument image therefore can be improved.

Third Embodiment

In the third embodiment, the cooperative operation between image formingunit 30 and server 50 in an OCR process will be described as an exampleof a case where image forming unit 30 and server 50 cooperate to performimage processing. The hardware configuration and the functionalconfiguration related to data transfer of the image forming apparatus inthe third embodiment are similar to those described with reference toFIG. 2 and FIG. 3 in the first embodiment and will not be furtherelaborated.

Although server 50 alone has image processor 94 in FIG. 3, image formingunit 30 may also have a corresponding image processor. For example, suchimage processing that does not burden image forming unit 30 may beprocessed by the image processor provided in image forming unit 30,instead of the image processor 94 in server 50.

Referring to FIG. 2, FIG. 9A, and FIG. 9B, the control structure ofimage forming apparatus 500 will be described. FIG. 9A and FIG. 9B areflowcharts showing the procedure of an OCR process in image formingapparatus 500 in the third embodiment. In the present third embodiment,the document image scanned by image forming unit 30 undergoes an OCRprocess in server 50, and data generated as a result of the process isreturned to image forming unit 30. While the dialog with a user and theoverall control are executed by CPU 32 of image forming unit 30, the OCRprocess that burdens the CPU is executed by server 50.

As shown in FIG. 9A, in step S550, CPU 32 of image forming unit 30 inFIG. 2 waits for user login.

In step S552, CPU 32 determines whether a user has logged in. If a userhas logged in (YES in step S552), CPU 32 stores login information andjob information into auxiliary storage device 33 or RAM 35 and proceedsto step S554. If a user has not logged in (NO in step S552), CPU 32returns to step S550.

In step S554, CPU 32 notifies CPU 51 of server 50 of the user's logininformation stored in auxiliary storage device 33 or RAM 35 throughnetwork controller 39. CPU 32 of image forming unit 30 then proceeds tostep S556.

In step S500, CPU 51 of server 50 receives the login informationtransmitted from image forming unit 30 through network controller 55 andproceeds to step S502.

In step S502, CPU 51 updates the storage area for login information inauxiliary storage device 53 or RAM 54 with the received logininformation and then proceeds to step S504.

In step S504, CPU 51 starts an application for OCR based on aninstruction by the user through input device 37.

In step S556, CPU 32 of image forming unit 30 notifies server 50 of thejob information stored in auxiliary storage device 33 or RAM 35 throughnetwork controller 39 and proceeds to step S558.

In step S506, CPU 51 of server 50 receives notification of the jobinformation from image forming unit 30 through network controller 55.

In step S558, CPU 32 of image forming unit 30 notifies server 50 of thejob start through network controller 39 and proceeds to step S560.

In step S508, CPU 51 of server 50 receives notification of the job startfrom image forming unit 30 through network controller 55.

In step S560, CPU 32 of image forming unit 30 instructs scanner 40 toscan a document, and scanner 40 starts a scan. CPU 32 then notifiesserver 50 of the start of document reading through network controller39.

In step S510, CPU 51 of server 50 receives the notification of documentreading transmitted from image forming unit 30 through networkcontroller 55.

In step S562, CPU 32 (that is, communication protocol selector 90 inFIG. 3) of image forming unit 30 determines whether the job iscooperating with an application on server 50, based on the jobinformation. If CPU 32 determines that the job is cooperating with anapplication on server 50 (YES in step S562), the process proceeds tostep S566. This is the case with the present embodiment in which CPU 32of image forming unit 30 transfers a document image generated by scanner40 to server 50. In step S566, CPU 32 selects UDP as the communicationprotocol of the transport layer in transmission of data from imageforming unit 30 to server 50. CPU 32 thereafter proceeds to step S568.

On the other hand, in step S562, if CPU 32 (that is, communicationprotocol selector 90 in FIG. 3) determines that the job is notcooperating with an application on server 50 (NO in step S562), theprocess proceeds to step S564. Examples include a case where the serverperforms an OCR process on the document image read by another imageforming apparatus connected to external network 510. In step S564, CPU32 selects TCP as the communication protocol of the transport layer intransmission of data from image forming unit 30 to server 50.

In step S568, CPU 32 (that is, transceiver 100 in FIG. 3) transmits theimage data scanned by scanner 40 to server 50 through network controller39. When image data is transferred, the communication protocol selectedin step S564 or step S566 is used. In this process example, server 50and image forming unit 30 are cooperating, and CPU 32 transfers thescanned image data to server 50 using UDP as the communication protocolof the transport layer.

In step S512, CPU 51 of server 50 receives the image data transmittedfrom image forming unit 30 through network controller 55 and stores theimage data into auxiliary storage device 53.

In step S514, CPU 51 starts an OCR process on the image data stored inauxiliary storage device 53.

In step S570, CPU 32 of image forming unit 30 terminates documentreading by scanner 40 and terminates transmission of the read documentimage to server 50 through network controller 39.

In step S516, CPU 51 of server 50 confirms termination of transmissionof the image to server 50 by image forming unit 30.

In step S518, CPU 51 completes the OCR process and thereafter proceedsto step S520.

In step S520, CPU 51 generates a file as a result of the OCR process andproceeds to step S522.

In step S522, CPU 51 (that is, communication protocol selector 90 inFIG. 3) of server 50 determines whether the job is cooperating with anapplication on image forming unit 30, based on the job information. IfCPU 51 determines that the job is cooperating with an application onimage forming unit 30 (YES in step S522), the process proceeds to stepS526. This is the case with the present embodiment in which CPU 51 ofserver 50 transfers the result of the OCR process to image forming unit30. In step S526, CPU 51 selects UDP as the communication protocol ofthe transport layer in transmission of data from server 50 to imageforming unit 30. CPU 32 thereafter proceeds to step S528.

On the other hand, in step S522, if CPU 51 (that is, communicationprotocol selector 90 in FIG. 3) determines that the job is notcooperating with an application on image forming unit 30 (NO in stepS522), the process proceeds to step S524. Examples include a case whereCPU 51 of server 50 transmits a file generated as a result of the OCRprocess to another image forming apparatus connected to external network510. In step S524, CPU 32 selects TCP as the communication protocol ofthe transport layer in transmission of data from server 50 to imageforming unit 30.

In step S528, CPU 51 (that is, transceiver 100 in FIG. 3) transmits thefile generated in step S520 to image forming unit 30 through networkcontroller 55 and proceeds to step S530. In file transfer, thecommunication protocol selected in step S524 or step S526 is used. Inthis process example, server 50 and image forming unit 30 arecooperating, and CPU 51 transfers the generated file to image formingunit 30 using UDP as the communication protocol of the transport layer.

In step S572, CPU 32 of image forming unit 30 receives the filetransmitted from server 50 through network controller 39 and stores thefile into auxiliary storage device 33. CPU 32 thereafter proceeds tostep S574.

In step S530, CPU 51 of server 50 terminates the application for OCR.

In step S574, CPU 32 of image forming unit 30 transmits the file storedin auxiliary storage device 33 in step S572 to the specified destinationthrough network controller 39. The specified destination includes adevice connected to external network 510.

In step S576, CPU 32 stores logout information into auxiliary storagedevice 33 or RAM 35 in response to the user logging out using inputdevice 37 and proceeds to step S578.

In step S578, CPU 32 notifies server 50 of the logout information storedin auxiliary storage device 33 or RAM 35 in step S576 through networkcontroller 39 and terminates a series of process steps in image formingunit 30.

In step S532, CPU 51 of server 50 receives the logout information fromimage forming unit 30 through network controller 55 and proceeds to stepS534.

In step S534, CPU 51 updates the storage area for logout information inauxiliary storage device 53 or RAM 54 with the received logoutinformation and terminates a series of process steps in server 50.

Effects of Third Embodiment

In the image forming apparatus in the third embodiment, when a documentimage generated by image forming unit 30 is transferred to server 50 inorder to use the image processing function such as OCR process, and whenserver 50 transfers data of a file generated as a result of imageprocessing to image forming unit 30, data is transmitted using UDP. Theoverall time required for the OCR process thus can be reduced.

Fourth Embodiment

In a fourth embodiment, the cooperative operation between image formingunit 30 and server 50 when image forming unit 30 accesses server 50 anduses a pull print function of printing data accumulated in server 50will be described. The pull print function also includes a case wherethe image forming apparatus accesses a storage device external to theimage forming apparatus and data accumulated in the storage device isprinted in the image forming apparatus. The hardware configuration andthe functional configuration related to data transfer of the imageforming apparatus in the fourth embodiment are similar to thosedescribed with reference to FIG. 2 and FIG. 3 in the first embodimentand will not be further elaborated.

FIG. 10A and FIG. 10B are flowcharts showing the procedure of pull printin image forming apparatus 500 in the fourth embodiment.

Referring to FIG. 2 and FIG. 10A, in step S650, CPU 32 of image formingunit 30 waits for user login. Since the function in the present fourthembodiment is the function implemented mainly by an application on imageforming unit 30, login is determined in image forming unit 30.

In step S652, CPU 32 determines whether a user has logged in. If a userhas logged in (YES in step S652), CPU 32 stores login information andjob information into auxiliary storage device 33 or RAM 35 and proceedsto step S654. If a user has not logged in (NO in step S552), CPU 32returns to step S650.

In step S654, CPU 32 notifies CPU 51 of server 50 of the user's logininformation stored in auxiliary storage device 33 or RAM 35 throughnetwork controller 39. CPU 32 of image forming unit 30 then proceeds tostep S656.

In step S600, CPU 51 of server 50 receives the login informationtransmitted from image forming unit 30 through network controller 55 andproceeds to step S602.

In step S602, CPU 51 updates the storage area for login information inauxiliary storage device 53 or

RAM 54 with the received login information and then proceeds to stepS604.

In step S604, CPU 51 starts an application for pull print based on aninstruction by the user through input device 37.

In step S656, CPU 32 of image forming unit 30 notifies server 50 of thejob information stored in auxiliary storage device 33 or RAM 35 throughnetwork controller 39 and proceeds to step S658.

In step S606, CPU 51 of server 50 receives notification of the jobinformation from image forming unit 30 through network controller 55.

In step S658, CPU 32 of image forming unit 30 starts the job, notifiesserver 50 of the job start through network controller 39, and proceedsto step S660.

In step S608, CPU 51 of server 50 receives notification of the job startfrom image forming unit 30 through network controller 55.

In step S660, the user specifies a file that the user wishes to print(hereinafter referred to as pull print file) from among data accumulatedin ROM 52 of server 50 through input device 37. CPU 32 of image formingunit 30 thereafter requests CPU 51 of server 50 to transmit the pullprint file to image forming unit 30 through network controller 55, inresponse to the user's instruction. In doing so, CPU 32 uses TCP as thecommunication protocol.

In step S610, CPU 51 of server 50 receives the request for the pullprint file through network controller 55 and proceeds to step S612.

In step S612, CPU 51 (that is, communication protocol selector 90 inFIG. 3) determines whether the request for the pull print file is arequest from the image forming unit connected to the same local network,based on the job information. If CPU 51 determines that the request forthe pull print file is a request from image forming unit 30 connected tothe same local network (YES in step S612), the process proceeds to stepS616. In step S616, CPU 51 selects UDP as the communication protocol ofthe transport layer in transmission of data from server 50 to imageforming unit 30. CPU 51 then proceeds to step S618.

On the other hand, in step S612, if the request for the pull print fileis not a request from the image forming unit connected to the same localnetwork (NO in step S612), CPU 51 (that is, communication protocolselector 90 in FIG. 3) proceeds to step S614. Examples include a casewhere a pull print process is performed on image data stored in astorage device connected to external network 510. In this case, in stepS614, CPU 32 selects TCP as the communication protocol of the transportlayer in transmission of data from server 50 to image forming unit 30.CPU 51 then proceeds to step S618.

In step S618, CPU 51 (that is, transceiver 100 in FIG. 3) transmits thepull print file to image forming unit 30 through network controller 55and proceeds to step S620. UDP selected in step S614 or TCP selected instep S616 is used as the communication protocol of the transport layerin data transfer.

In step S662, CPU 32 of image forming unit 30 receives the pull printfile transmitted from server 50 through network controller 39 andproceeds to step S664.

In step S620, CPU 51 of server 50 terminates the application for pullprint.

In step S664, CPU 32 of image forming unit 30 sends an instruction toprinter 41 to print the pull print file received in step S662.

In step S666, CPU 32 stores logout information into auxiliary storagedevice 33 or RAM 35 in response to the user logging out using inputdevice 37 and proceeds to step S668.

In step S668, CPU 32 notifies server 50 of the logout information storedin auxiliary storage device 33 or RAM 35 in step S666 through networkcontroller 39 and terminates a series of process steps in image formingunit 30.

In step S622, CPU 51 of server 50 receives the logout information fromimage forming unit 30 through network controller 55 and proceeds to stepS624.

In step S624, CPU 51 updates the storage area for logout information inauxiliary storage device 53 with the received logout information andterminates a series of process steps in server 50.

Effects of Fourth Embodiment

The image forming apparatus in the fourth embodiment uses UDP intransfer of data of a pull print file between image forming unit 30 andserver 50, thereby reducing the time required for data transfer. As aresult, the time required for a pull print process can be reduced. Whenthe transfer destination of a pull print file is a device connected toexternal network 510, TCP is used as a communication protocol, therebyincreasing the reliability of communication. In the case where the pullprint file is image data, it practically does not matter even if UDPthat does not ensure the reliability of communication is used andconsequently, image data is printed with some pixels missing due to acommunication error due to noise or the like.

<Modifications>

Although TCP is employed as an example of the first protocol and UDP isemployed as an example of the second protocol in the present disclosure,the range of application of the disclosed technical idea is not limitedthereto. Although the TCP/IP model is used as a network model in thepresent disclosure, the above range is not limited thereto.

Although embodiments of the present invention have been described andillustrated in detail, the disclosed embodiments are made for purposesof illustration and example only and not limitation. The scope of thepresent invention should be interpreted by terms of the appended claims

What is claimed is:
 1. An image forming apparatus comprising: an imageforming unit including a scanner configured to scan a document togenerate image data and a printer configured to print image datagenerated by the scanner or another image data on a recording medium; aserver; and a local network circuit configured to connect the imageforming unit and the server, the image forming unit and the server eachincluding: a transceiver configured to transmit and receive data throughthe local network circuit; and a hardware processor, wherein thehardware processor of one of the image forming unit and the serverselects one of a first communication protocol and a second communicationprotocol in accordance with data transmitted by the transceiver of theone of the image forming unit and the server when data is transmitted bythe transceiver of the one to the transceiver of the other, the firstcommunication protocol includes a provision for ensuring reliability ofcommunication, and the second communication protocol does not include aprovision for ensuring reliability of communication.
 2. The imageforming apparatus according to claim 1, wherein the first communicationprotocol is Transmission Control Protocol (TCP), and the secondcommunication protocol is User Datagram Protocol (UDP).
 3. The imageforming apparatus according to claim 1, wherein the hardware processorof one of the image forming unit and the server selects the secondcommunication protocol when encoded data is transmitted by thetransceiver of the one to the transceiver of the other.
 4. The imageforming apparatus according to claim 3, wherein the encoding includes atleast one of compression, encryption, and data format conversion.
 5. Theimage forming apparatus according to claim 1, wherein the hardwareprocessor of one of the image forming unit and the server selects thesecond communication protocol when data transmitted by the transceiverof the one to the transceiver of the other includes an error detectioncode.
 6. The image forming apparatus according to claim 1, wherein thehardware processor of one of the image forming unit and the serverselects the second communication protocol when a size of datatransmitted by the transceiver of the one to the transceiver of theother is equal to or greater than a predetermined threshold.
 7. Theimage forming apparatus according to claim 1, wherein the hardwareprocessor of the image forming unit selects the second communicationprotocol when image data generated by the scanner is transmitted by thetransceiver of the image forming unit to the transceiver of the server.8. The image forming apparatus according to claim 1, wherein the localnetwork circuit is connected to an external network through a securitygateway.
 9. The image forming apparatus according to claim 8, whereinthe hardware processor of the image forming unit selects the firstcommunication protocol when image data generated by the scanner istransmitted by the transceiver of the image forming unit to a deviceconnected to the external network.
 10. The image forming apparatusaccording to claim 1, wherein the hardware processor of the imageforming unit selects the second communication protocol when an image login which a log of a job executed by the image forming unit is stored asimage data is transmitted by the transceiver of the image forming unitto the transceiver of the server.
 11. The image forming apparatusaccording to claim 1, wherein the hardware processor of the serverselects the second communication protocol when import data for changingsetting information of the image forming unit is transmitted by thetransceiver of the server to the transceiver of the image forming unit.12. The image forming apparatus according to claim 1, wherein thehardware processor of the image forming unit selects the secondcommunication protocol when export data for backing up current settinginformation of the image forming unit is transmitted by the transceiverof the image forming unit to the transceiver of the server.
 13. Theimage forming apparatus according to claim 1, wherein the hardwareprocessor of the server selects the second communication protocol whenupdate data of firmware for the image forming unit is transmitted by thetransceiver of the server to the transceiver of the image forming unit.14. The image forming apparatus according to claim 1, wherein thehardware processor of the server selects the second communicationprotocol when data stored in the server is transmitted by thetransceiver of the server to the transceiver of the image forming unitand the stored data is printed by the printer of the image forming unit.15. The image forming apparatus according to claim 1, wherein thehardware processor of the server performs image processing on image datagenerated by the scanner, and the hardware processor of the serverselects the second communication protocol when data generated as aresult of the image processing is transmitted by the transceiver of theserver to the transceiver of the image forming unit.
 16. The imageforming apparatus according to claim 15, wherein the image processingincludes an optical character recognition (OCR) process.
 17. A datatransfer method in an image forming apparatus, the image formingapparatus including: an image forming unit including a scannerconfigured to scan a document to generate image data and a printerconfigured to print image data generated by the scanner or another imagedata on a recording medium; a server; and a local network circuitconfigured to connect the image forming unit and the server, the datatransfer method comprising: selecting one of a first communicationprotocol and a second communication protocol in accordance with data tobe transmitted, by a transmitter side of the image forming unit and theserver, when data is transferred between the image forming unit and theserver through the local network circuit; and transmitting data by thetransmitter side to a receiver side using the selected communicationprotocol, wherein the first communication protocol includes a provisionfor ensuring reliability of communication, and the second communicationprotocol does not include a provision for ensuring reliability ofcommunication.